setup_git_directory: fix segfault if repository is found in cwd

diff --git a/builtin-branch.c b/builtin-branch.c
index 7408285050a0f41a33d31c73e79c2fdefe567593..67f46c1ae2fd28fe6b4baffdf3447df7904cc021 100644 (file)
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -317,8 +317,6 @@ static void print_ref_list(int kinds, int detached, int verbose, int abbrev)
 static char *config_repo;
 static char *config_remote;
 static const char *start_ref;
-static int start_len;
-static int base_len;
 
 static int get_remote_branch_name(const char *value)
 {
@@ -334,26 +332,41 @@ static int get_remote_branch_name(const char *value)
 
        end = value + strlen(value);
 
-       /* Try an exact match first.  */
+       /*
+        * Try an exact match first.  I.e. handle the case where the
+        * value is "$anything:refs/foo/bar/baz" and start_ref is exactly
+        * "refs/foo/bar/baz". Then the name at the remote is $anything.
+        */
        if (!strcmp(colon + 1, start_ref)) {
-               /* Truncate the value before the colon.  */
+               /* Truncate the value before the colon. */
                nfasprintf(&config_repo, "%.*s", colon - value, value);
                return 1;
        }
 
-       /* Try with a wildcard match now.  */
-       if (end - value > 2 && end[-2] == '/' && end[-1] == '*' &&
-           colon - value > 2 && colon[-2] == '/' && colon[-1] == '*' &&
-           (end - 2) - (colon + 1) == base_len &&
-           !strncmp(colon + 1, start_ref, base_len)) {
-               /* Replace the star with the remote branch name.  */
-               nfasprintf(&config_repo, "%.*s%s",
-                          (colon - 2) - value, value,
-                          start_ref + base_len);
-               return 1;
-       }
+       /*
+        * Is this a wildcard match?
+        */
+       if ((end - 2 <= value) || end[-2] != '/' || end[-1] != '*' ||
+           (colon - 2 <= value) || colon[-2] != '/' || colon[-1] != '*')
+               return 0;
 
-       return 0;
+       /*
+        * Value is "refs/foo/bar/<asterisk>:refs/baz/boa/<asterisk>"
+        * and start_ref begins with "refs/baz/boa/"; the name at the
+        * remote is refs/foo/bar/ with the remaining part of the
+        * start_ref.  The length of the prefix on the RHS is (end -
+        * colon - 2), including the slash immediately before the
+        * asterisk.
+        */
+       if ((strlen(start_ref) < end - colon - 2) ||
+           memcmp(start_ref, colon + 1, end - colon - 2))
+               return 0; /* does not match prefix */
+
+       /* Replace the asterisk with the remote branch name.  */
+       nfasprintf(&config_repo, "%.*s%s",
+                  (colon - 1) - value, value,
+                  start_ref + (end - colon - 2));
+       return 1;
 }
 
 static int get_remote_config(const char *key, const char *value)
@@ -363,10 +376,12 @@ static int get_remote_config(const char *key, const char *value)
                return 0;
 
        var = strrchr(key, '.');
-       if (var == key + 6)
+       if (var == key + 6 || strcmp(var, ".fetch"))
                return 0;
-
-       if (!strcmp(var, ".fetch") && get_remote_branch_name(value))
+       /*
+        * Ok, we are looking at key == "remote.$foo.fetch";
+        */
+       if (get_remote_branch_name(value))
                nfasprintf(&config_remote, "%.*s", var - (key + 7), key + 7);
 
        return 0;
@@ -392,14 +407,14 @@ static void set_branch_merge(const char *name, const char *config_remote,
 
 static void set_branch_defaults(const char *name, const char *real_ref)
 {
-       const char *slash = strrchr(real_ref, '/');
-
-       if (!slash)
-               return;
-
+       /*
+        * name is the name of new branch under refs/heads;
+        * real_ref is typically refs/remotes/$foo/$bar, where
+        * $foo is the remote name (there typically are no slashes)
+        * and $bar is the branch name we map from the remote
+        * (it could have slashes).
+        */
        start_ref = real_ref;
-       start_len = strlen(real_ref);
-       base_len = slash - real_ref;
        git_config(get_remote_config);
        if (!config_repo && !config_remote &&
            !prefixcmp(real_ref, "refs/heads/")) {
@@ -462,7 +477,7 @@ static void create_branch(const char *name, const char *start_name,
                die("Not a valid branch point: '%s'.", start_name);
        hashcpy(sha1, commit->object.sha1);
 
-       lock = lock_any_ref_for_update(ref, NULL);
+       lock = lock_any_ref_for_update(ref, NULL, 0);
        if (!lock)
                die("Failed to lock ref for update: %s.", strerror(errno));
 
@@ -623,9 +638,10 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
            (rename && force_create))
                usage(builtin_branch_usage);
 
-       head = xstrdup(resolve_ref("HEAD", head_sha1, 0, NULL));
+       head = resolve_ref("HEAD", head_sha1, 0, NULL);
        if (!head)
                die("Failed to resolve HEAD as a valid ref.");
+       head = xstrdup(head);
        if (!strcmp(head, "HEAD")) {
                detached = 1;
        }